STARLab Research Meeting July 7, 2006

Relevance Computation

Aldo de Moorademoor@vub.ac.be

Relevance computation

• Usefulness of definitions, efficiency of ontology engineering process very important

• Key problem: how to assess continuously shifting relevance of evolving common definitions?

• Essential to ensure scalability • Example: how to select relevant

organizational specializations?

Org Ontologies (dOi + CTHOi)

T > Product > Beklede_Bakvorm Kwaliteit > Geen_Luchtbellen Gelijke_Dikte

Interorganizational Ont Eng

UCO

LCO

OO-1 OO-n

IOO v_1UCO

LCO

OO-1 OO-n

IOO v_m

A Selection Procedure (1)

• Pre-condition: all org. ontologies updated• Post-condition: ready to start IOO_v+1• Core domain expert defines set of relevance definitions

DR = {dr1, ...}, e.g.:

A Selection Procedure (2)

• Each dr DR is used to create set of relevance relations RR, e.g.:

A Selection Procedure (3)

• For each org. ontology OOi

– For each org. spec. dOi OOi, calculate relevance score sr by projecting all relevance relations into the definition:

• (Using the organizational concept type hierarchy CTHOi)

• Sr(dOi) = 0.• For each rr RR: if :rr → dOi, then Sr(dOi) := Sr(dOi) +

1– Select most relevant org. spec. using this relevance

score• x highest-ranked specializations (overall, by organization)• Those specializations meeting particular threshold.

– Further, scalable contextualization: use lexonized relevance relations to select relevant resources from lexon / commitments-base

Lexonizing Relevance Relations

(NBC CTH)T > Product > Beklede_Bakvorm Kwaliteit > Geen_Luchtbellen Gelijke_Dikte

...

Discussion

• Relevance computation helps scale interorganizational ontology engineering

• Relevance relation: in between full-graph and concept matching level (e.g. crawler Felix). When to apply which type of technique?

• Only heuristic: human evaluation still very much needed. When? What? How?

• Relevance relations = sets of lexons – ground CGs (larger patterns) in real-world semantics (lexons)– do a wide, lexon-driven scan of ontological resources

• How to use ORM constraints to further tailor relevance computation?